Indentation, scratch, tensile and compression testing at scales of microns or less are methods for quantitatively measuring mechanical properties, such as elastic modulus and hardness, of materials. For instance, probes capable of determining loading forces and displacement are used. In some examples, forces applied in mechanical testing at scales of microns or less are less than 10 N, with a typical displacement range being smaller than 500 μm, and with a noise level typically being better than 10 nm root mean square (rms). Force and displacement data measured with the probe are used to determine the mechanical properties of the sample and one or more of the elastic or plastic characteristics and the associated material phase changes. In one example, for sample property estimation a micro/nano-indenter is integrated with a characterized indenter tip having a known geometry and known mechanical properties.
Some of the emerging mechanical characterization techniques at scales of microns or less include, but are not limited to, quantitative transmission electron microscopy (TEM) and scanning electron microscopy (SEM) in-situ mechanical testing (as well as optical microscope techniques in some instances). These in-situ mechanical testing techniques enable monitoring of the deformation of a sample in real time while measuring the quantitative mechanical data. Coupling a mechanical testing system configured for testing at scales of microns or less with electron or optical microscopy imaging allows researchers to study structure property correlation and the influence of pre-existing defects on the mechanical response of materials. In addition to imaging, selected-area diffraction can be used to determine sample orientation and loading direction influence on mechanical response. Moreover, with in-situ electron or optical microscopy mechanical testing, the deformation can be viewed in real-time rather than “post-mortem”. Performing in-situ mechanical testing at scales of microns or less can provide unambiguous differentiation between the many possible causes of force or displacement transients which may include dislocation bursts, phase transformations, shear banding or fracture onset. Mechanical testing at micron or nano scales with elevated temperature is an important part of material characterization for materials having phase changes or variant mechanical properties as temperature increases. Many materials and devices are designed to perform at temperatures other than room temperature. The thermo-mechanical reliability of advanced materials needs to be fully understood through proper material testing. Due to this reason, it is often preferred to test the mechanical properties of these materials at their operating temperatures. The measured data at the elevated temperature can be used to estimate the performance of the materials in their normal operating environment. For example, understanding the thermo-mechanical response of polymer composites designed for enhanced mechanical properties will result in lighter and stronger materials for the aerospace and automobile industries, improving efficiency in the transportation sector and energy savings. Understanding the fundamentals of strengthening mechanisms in ceramic matrix composite materials will help to improve the lifetime usage of these materials in real world applications. To improve the efficiency of turbine powered jet engines, new turbines must run hotter with less cooling. Understanding the mechanical properties at elevated temperature of individual components such as disks, blades and nozzles is critical for the aerospace industry.